Pratap Singh was a popular Maratha ruler of Thanjavur from 1739 to 1763. His rise to power was actually followed three years of civil war and anarchy and restored the state to its previous greatness. His reign witnessed the Carnatic Wars and the Seven Years War.

Early Life of Pratap Singh
Pratapsingh was born to Tukkoji, the Raja of Thanjavur and a concubine Annapurna. In the beginning he was not expected to rule as he was not the legitimate son of the Raja. However, the premature death of the king`s eldest son Ekoji II who died after ruling Thanjavur for a year and a period of anarchy which followed thrust Pratap Singh on the forefront of palace intrigues.

Period of Anarchy 1736-1739
A period of anarchy followed after the death of Tukkoji in 1736. Ekoji, the eldest son of the king and heir apparent succeeded to the throne but died after ruling Thanjavur for a year. Nonetheless, despite his poor health, Ekoji offered a determined resistance to Chanda Sahib who invaded Thanjavur during the former`s short reign and forced him to retreat to Tiruchirapalli.

In the year 1737, Ekoji died and was succeeded by his wife Sujanbai. Sayyid, the Governor of the Thanjavur Fort, rose into prominence during this period as a kingmaker and actively participated in court intrigues promoting one puppet ruler after another to the throne. He imprisoned Sujanbai in 1738 when the latter questioned his authority.

Shahuji returned in 1738 and ruled for about a year. In February 1739, Chanda Sahib forced Shahuji to cede Karaikal to the French and in April, the Raja confirmed the Grant. In July 1739, Shahuji prevented the French from landing in Karaikal. This resulted in invasion of Thanjavur by Chanda Sahib who captured Shahuji and imprisoned him on the pretext that he was not the actual Shahuji but an impostor.

Reign of Pratap Singh
In the year 1739, Pratap Singh ascended the throne. He was the last ruler of Thanjavur to be referred in the official records of the English East India Company as "His Majesty". As soon Pratap Singh got to the throne he had to settle with the manoeuvring of the pretender Shahuji in the company of a treacherous Maratha noble Koyaji Kattigai. It was also evident that the conspirators were in league with Shahuji in the company of a treacherous Maratha noble Koyaji Kattigai.

In the year 1748, the pretender Shahuji sent an envoy, first to Puducherry, and then to Fort St. David to negotiate the terms and alliance with the French East India Company. Initially, Pratap Singh was supported by British East India Company but switched sides when Shahuji offered Devikottai. The British sent two expeditions against Devikkottai which was defended by a garrison of 5,000 men. Their first attempt was a complete failure while second ended in truce. Second expedition, however, was incredible as the one in which Lawrence and Clive distinguished them. Finally a treaty between Company and Pratap Singh finally led to the end of war. Devikkottai was made over to the English as per the provisions of the treaty.

Pratap Singh, in the early part of his reign, had to deal with the authoritative attitude of Dost Ali, the Nawab of the Carnatic. Soon, Pratap Singh was deposed by Dost Ali who took over the administration of Thanjavur. But a Maratha invasion from the north brought about the death of Dost Ali and the restoration of Pratap Singh. The Maratha troops left after making one Murari Rao the ruler of Tiruchirapalli with whom Pratap Singh was in bad terms. Soon afterwards, the Nizam of Hyderabad sent a formidable force to Thanjavur to exact tribute. Two other expeditions forced the Raja into submission.

The third and final expedition of the Nizam of Hyderabad in 1742 resulted in the deposition of Murari Rao and the annexation of Tiruchirapalli. As a result of this campaign, Thanjavur was forced to become a vassal of Hyderabad and pay annual tribute.

The Seven Years War
During the Seven Years War, Pratap Singh supported the English with arms and supplies. At Lawrences` behest, the great Thanjavur general Manoji took Coillady from the French and captured Chanda Sahib and beheaded him.

However, the confederacy broke when Nanja Raja realized that he had been deceived by Muhammad Ali who had promised to give him Tiruchirapalli as per an early arrangement. Pratap Singh supported his cause when the French under Dupleix tried to threaten him. Muhammad Ali and Murari Rao forged an alliance with the French.

In the year 1758, Lally marched to Thanjavur from Karaikal in order to force Thanjavur into subjugation but was repulsed by Manoji. He had to retreat with an insignificant plunder at Nagore when an English fleet made its appearance off the coast at Karaikal. The Thanjavur troops supported by a small English contingent harassed the French who eventually succumbed to starvation. The British inflicted a crushing defeat on the French in the siege of Puducherry in 1761. This dealt a death-blow to the French power in India.

Death of Pratap Singh
On 16 December 1763, after reigning for 24 years, Pratap Singh died. His third and fifth queens committed Sati. He was succeeded by his eldest son Thuljaji.